Levelling up the coding of a command-line program in JavaScript

You must have heard about Node.js. This is an open source cross-platform development environment that allows the creation of web-servers, networking, and other tools using JavaScript. Node.js extends classical JavaScript with a collection of specialized modules. These modules handle filesystem I/O, networking, OS-level operations, binary data, cryptography functions, data streams, and others (https://nodejs.org/api/index.html). Node.js uses an event-driven I/O model. Similar to JavaScript, it operates on single-thread performing non-blocking calls. So time consuming functions can run concurrently by invoking a callback when it completes.

To get the feel of Node.js, we start with an example that simply prints Hello world:

hello.js

console.log( "Hello world!" );

Now let's open the console (command-line interface: CMD in Windows, or Terminal in Linux and Mac OS), navigate to the example script location, and run the following:

node...